This invention relates to the field of spectrum analysis of electronic signals, and more particularly to the field of methods and apparatuses for identifying, saving, and analyzing continuously generated frequency domain information.
Digital spectrum analyzers have been able to acquire data faster than they can process it. And, as they improve their capabilities for processing data, they often can process data faster than they can display it. This display `bottleneck` results in discontinuities in the displayed data. That is, while one set of data is being displayed, additional data is acquired, processed, and lost before the display mechanism is ready to display another set of data. This means that data presented to the operator as contiguous or sequential, is in fact interspersed with gaps.
Further, triggers have been used in spectrum analyzers to start acquisition, or stop it, but these have always been triggers based on time domain information about the input signal under analysis, or triggers derived from some external source, not triggers derived from frequency domain information. And, while some spectrum analyzers have had means for identifying a spectral event for the purpose of providing a go/no-go indication, previously no spectrum analyzer has used the identification of a spectral event to trigger data acquisition or data storage.
What is desired is a method of identifying a spectral event, that is an event defined in the frequency domain, and, in response to that identification, or in response to a command from an operator, being able to accumulate and display for operator analysis all of the data pertaining to some particular interval of interest, so multiple frequency spectra that fully describe a continuous history of the activity of the signal in the time domain over the period of interest may be viewed and analyzed by the operator of a spectrum analyzer.